1. Field of the Invention
The present invention relates to a motor controller for a driving unit used in processing machines, semiconductor manufacturing equipment, various conveyance equipment, or the like.
2. Description of the Related Art
A motor controller needs to generate torque commands through a computation by a feedback loop based on a motor speed or a motor angle, and to properly set out a zero-point frequency, a filter frequency, and a pole and a zero point of a transfer function of the feedback loop and the like related to the loop gain and a speed PI control. It takes a time to individually adjust those; in addition, it is difficult for beginners to adjust those because they need knowledge to properly make the adjustment.
Prior art that improves these adjustment described above, for example, is to configure the controller in such a way that one input parameter is inputted from outside and then the loop gain, pole and zero point of the transfer function of the feedback loop are set out using a specific relational equation derived from the input parameter, enabling the adjustment by one parameter to be easily made (Refer to Patent Document 1; Japanese Patent Laid-Open No. 27784/2002).
There have been problems in that not only it needs manpower and takes a time to make good adjustments in setting out individually a loop gain of a feedback loop, a pole frequency, a zero-point frequency, and the like, but also it is difficult without specialized knowledge.
In a system in which adjustment are made by one input parameter as described in the above Patent Document 1, in general, such a simple model of a controlled object as approximates a most common inertia body (rigid body) is considered, and then a relational equation based on the one parameter described above is determined, so that the system suits to general-use application and controlling specifications.
However, an actual controlled object has characteristics such as mechanical resonances at different frequencies, resulting in its various characteristics. In addition, controlling specifications are not standardized in such a point as to which is more prioritized, converging speed or response smoothness, depending on the applications in which the motor controlled is employed.
As a result, there have been problems in that conventional motor controller can not reach a properly adjust state by only adjustment by means of one input parameter, causing, in some cases, adjustment each being greatly deviated from the proper adjustments.